Alkanes
Chapter Name : Hydrocarbons |
Sub Topic Code : 102_11_13_02_14 |
Topic Name : Alkanes |
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Sub Topic Name : Pyrolysis |
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Introduction
Alkanes consist only of hydrogen and carbon atoms, all bonds are single bonds, and the carbon atoms are not joined in cyclic structures but instead form an open chain. They have the general chemical formula CnH2n+2.
Pre-Requisites:
Pyrolysis
Activity:
Crude oil.
Real Life Question:
What is Pyrolysis?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Pyrolysis | Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen (or any halogen). It involves the simultaneous change of chemical composition and physical phase, and is irreversible. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| liquefied petroleum gas | A flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. |
Real life uses :
The process is used heavily in the chemical industry, for example, to produce charcoal, activated carbon, methanol, and other chemicals from wood, to convert ethylene dichloride into vinyl chloride to make PVC, to produce coke from coal, to convert biomass into syngas and bio char, to turn waste into safely disposable substances, and for transforming medium-weight hydrocarbons from oil into lighter ones like gasoline.
Places to visit :
Chemistry laboratory.
Practical examples around us
| Examples | Explainations |
|---|---|
| Ethane | A chemical compound with chemical formula C2H6. At standard temperature and pressure, ethane is a colorless, odorless gas. Ethane is isolated on an industrial scale from natural gas, and as a byproduct of petroleum refining. Its chief use is as petrochemical feedstock for ethylene production. |
What you learn in Theory:
Pyrolysis differs from other high-temperature processes like combustion and hydrolysis in that it usually does not involve reactions with oxygen, water, or any other reagents. In practice, it is not possible to achieve a completely oxygen-free atmosphere. Because some oxygen is present in any pyrolysis system, a small amount of oxidation occurs.
What you learn in Practice:
Pyrolysis occurs whenever food is exposed to high enough temperatures in a dry environment, such as roasting, baking, toasting, or grilling. It is the chemical process responsible for the formation of the golden-brown crust in foods prepared by those methods.